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6. (25%) Consider the voltage amplifier of Fig. 6 with a BJT device having β = 100 when it is biased in the active region. The coupling capacitors C₁ = C₂ = C₃ = 1 μF. The voltage supplies are 5 V and the thermal voltage VT= 25.9 mV. If the transistor is specified to have f_T = 700 MHz and C_μ = 1 pi. The constant voltage drop 0.7 V approximation can be used for the turn-on of a p-n junction. In addition. other resistances are also included in the Fig. 6. Please calculate (a)f₁，f₂，f₃ (let f₁ ＜f₂＜f₃) values of the low-frequcncy transfer function (b) the upper 3-dB frequcncy f_Hby using open-circuit time constants method if the ro and rx effect are neglected. (5%*3, 10%)